WASHINGTON (Reuters Life!) - The swine flu pandemic may have changed the U.S. approach to handling influenza forever, and for the better, U.S. officials said on Thursday.

While they said years of work were needed before vaccine production was up to the desired standard, some experiments such as vaccinating children in schools might work to help control seasonal influenza.

But there are still holes in the public health system that will take years to patch, and communication with the public could use a bit more polishing, they acknowledged.

"We still don't have the domestic capacity to make as much (flu vaccine) as we need as fast as we need it," Nicole Lurie, assistant secretary for preparedness and response at the Health and Human Services Department, told a news conference.

She said HHS had been forced by the H1N1 pandemic to work closely with state and local health officials to monitor the virus and deploy drugs and vaccines.

"I actually think our nation's preparedness, our seasonal flu efforts and so on, will never be the same," Lurie said.

HHS Secretary Kathleen Sebelius said 100 million H1N1 vaccines will have been delivered or would be ready for order by the end of the week. She urged Americans to get vaccinated now and said everyone, not just people on the priority lists, should feel free to get one.

"This is a serious flu that targets people who normally don't get seriously ill from the flu," Sebelius told the news conference.

"We have a chance to lessen the impact or even prevent a big third wave ... and we need to seize this opportunity right now," she said.

The U.S. Centers for Disease Control and Prevention estimates that 47 million Americans have been infected with H1N1, nearly 10,000 have been killed by it and more than 200,000 hospitalized.

EBBING SECOND WAVE

"The number of children and young adults killed by mid-November was five times more than in the average flu season," CDC Director Dr. Thomas Frieden said.

"We have an ebbing second wave but we have an uncertain future."

School vaccinations have worked well and CDC may press to keep the programs for seasonal influenza, Frieden said.

"Not only will vaccinating kids in school reduce the number of kids who get sick ... but may well also tamp down the spread of flu in a community," he said.

But Frieden fretted about losses to public health. The CDC reported that in 2009, 10 percent fewer epidemiologists were working in state health departments than in 2006. Those specialists in the spread and pattern of disease are key to keeping track of viruses like flu, Frieden said.

"This virus was undoubtedly circulating for several months before it was identified," Frieden said.

Had it been detected, he said, vaccine makers could have started work on a vaccine month earlier.

Frieden also noted there was confusion about how many vaccines would be available, and when. HHS has been criticized for at first saying 250 million vaccines would be produced, and then rolling back on the numbers that could be delivered.

"Clearly we need to do better at managing vaccine expectations," Frieden said.

Much work remains on improving vaccine technology, said Dr. Anthony Fauci, head of the U.S. National Institute of Allergy and Infectious Diseases. The goal is a so-called universal vaccine that would not have to be reformulated as the virus mutates every flu season.

"We need to harness the science to be able to make an influenza vaccine that not only is good from season to season but ... that doesn't change from season to season and from pandemic to pandemic," Fauci said.